At least 500 children and 276 women are among the estimated 1,537 Palestinians who have died with more than 6,000 wounded, the Gaza health ministry has said.

The total figure is 120 more deaths than the ministry reported this afternoon.

The number of fatalities in Gaza is expected to rise further as Israel's siege of the territory has left left Palestinians with dwindling supplies of food, water, electricity and medicine.

Israel has said it is targeting Hamas after the militant group carried out a wave of attacks in Israel at the weekend as gunmen stormed the border and killed hundreds in their homes as well as 260 others at a music festival.

US Secretary of State Anthony Blinken has been speaking on a visit to Israel this evening where he said the government had showed him photographs and videos of the victims of attacks by Hamas.

He said the images included a baby riddled with bullets, soldiers beheaded, and young people burned alive in their cars or hideaways.

Mr Blinken added: "If you look at [the incursion] in proportion to the size of Israel's population, this is the equivalent of ten 9/11s.

"That's how big and how devastating the attack has been."

Israel says a total of 1,300 of its people have died since Saturday's raid as its troops continue to mass along the barbed wire fence ahead of a possible ground offensive on Gaza, with 300,000 reservists called up.

Key developments:
• UK navy to send ships and begin surveillance flights over Israel
• Two UK Jewish schools close for safety reasons
• British-Israelis issue plea as families held hostage in Gaza
• Blinken tells Netanyahu the US will always be by Israel's side
• Israel reportedly strikes airports in Syria
• Israel says no food or water will be supplied to Gaza until hostages are freed
• UN warns of 'dire situation' in Gaza Strip
• Palestinians accuse Israel of killing civilians
• Israeli PM says Hamas beheaded soldiers and raped women
• Israeli military admits it failed to protect its citizens in Hamas attack

Israel 'strikes Syrian airports' - follow live conflict updates

Food and water in Gaza 'quickly running out'

Hamas has said 18 Palestinians died in the Nuseirat Refugee Camp in the heart of Gaza following one of the latest Israeli retaliatory raids.

Some 340,000 Palestinians have fled their homes seeking refuge in schools, according to the United Nations.

The UN World Food Programme (WFP) has warned crucial supplies were running dangerously low in the Gaza Strip after Israel imposed a total blockade on the territory.

"It's a dire situation in the Gaza Strip that we're seeing evolve with food and water being in limited supply and quickly running out," said Brian Lander, the deputy head of emergencies at WFP.

Read more:
Why Israel is braced for Hezbollah attack from Lebanon
How hostage negotiators will be working to free Hamas captives

Israel has insisted it is giving prior warning of its strikes, though they are now hitting entire neighbourhoods as opposed to individual buildings.

Meanwhile, the chief of staff for Israel's military, Herzi Halevi, admitted it failed to protect its civilians from Hamas's unprecedented attack on Saturday.

"The IDF is responsible for the security of the country and its citizens, and on Saturday morning in the area surrounding the Gaza Strip, we did not," Mr Halevi said. "We will learn, we will investigate, but now is the time for war."

The overnight retaliatory strikes targeted Hamas's elite Nukhba forces, including command centres used by the fighters who attacked Israel, and the home of a senior Hamas operative where unspecified weapons were stored, the Israeli military said.

Elsewhere, Israeli airstrikes have struck the international airports of the Syrian capital Damascus and the northern city of Aleppo, damaging their runways and putting them out of service, said Syrian state media.

An unnamed military official was quoted by the state news agency Sana as saying no one was hurt in the attacks. The Israeli military declined to comment.

The airstrikes came a day before Iran's foreign minister was scheduled to visit Syria to meet officials over the volatile situation in the region.

In the past, Israel has targeted airports and sea ports in the government-held parts of Syria in an apparent attempt to prevent arms shipments from Iran to militant groups backed by Tehran, including Lebanon's Hezbollah.

IDF troops assemble

Troops from the Israel Defence Forces (IDF) are building up near the Gaza border as an imminent ground invasion is possible - though no political decision on this has yet been announced, Lieutenant Colonel Richard Hecht said.

Israel has also evacuated tens of thousands of residents from nearby communities.

Should the ground offensive go ahead it would be the first since the 50-day Gaza war in 2014, which left thousands of Palestinians and dozens of IDF troops dead.

US trying to stop the conflict from spreading

The possible invasion of Gaza comes as Mr Blinken said the images he had seen of Israeli victims reflected "depravity in the worst imaginable way".

He added during his address in Tel Aviv: "Images are worth a thousand words. These images may be worth a million."

Mr Blinken also said the US is "working as hard as it can" to ensure the conflict does not open on a second front with involvement from Iran-backed Hezbollah, based in Lebanon.

"[Joe Biden] has been very clear that no one state or non-state actor should try to take advantage of this moment," he said.

Following his trip to Israel, Mr Blinken will head to Jordan to meet with King Abdullah and Palestinian Authority President Mahmoud Abbas, before travelling on to meet with leaders in Saudi Arabia, the United Arab Emirates, Egypt and Qatar.

The US secretary of state said he will be "pressing countries to help prevent the conflict from spreading".

Mr Blinken had earlier met with Israeli prime minister Benjamin Netanyahu in Tel Aviv today, where said the US would "always be there by [Israel's] side".

"You may be strong enough on your own to defend yourselves, but as long as America exists you will never have to," Mr Blinken said.

Mr Netanyahu announced a unity government on Wednesday and vowed to "crush and destroy" Hamas.

"Every Hamas member is a dead man," Mr Netanyahu said in a televised address. He has also called Hamas an "enemy of civilisation".

Israel estimates 1,500 Hamas militants have been killed on its soil following their infiltration of the border.

The IDF, which along with Western powers, considers Hamas as "terrorists".

Mr Netanyahu said that militants beheaded soldiers and raped women in its attack on Saturday.

Hamas is also believed to be holding around 150 hostages in Gaza, including soldiers, men, women, children and older adults, since the surprise weekend raid.

Israel's energy minister, Israel Katz, said the blockade would remain until the captives were released.

"Not a single electricity switch will be flipped on, not a single faucet will be turned on, and not a single fuel truck will enter until the Israeli hostages are returned home," he said on social media.

The US has stepped in by sending Israel a team of technical experts to assist with the recovery as it believes some of the captives are Americans.